cdc.gov/coronavirus

Myopericarditis following COVID-19 

vaccination: Updates from the Vaccine 

Adverse Event Reporting System (VAERS) 

Aug 30, 2021

John R. Su, MD, PhD, MPH

Vaccine Safety Team

CDC COVID-19 Vaccine Task Force
Disclaimer

 The findings and conclusions in this report are those of the authors 

and do not necessarily represent the official position of the Centers 

for Disease Control and Prevention (CDC) or the U.S. Food and Drug 

Administration (FDA)

 Mention of a product or company name is for identification 

purposes only and does not constitute endorsement by CDC or FDA

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Myopericarditis reports to VAERS

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Focusing analysis on reports of myocarditis and myocarditis with 

pericarditis (myopericarditis) following COVID-19 vaccination

 As of August 18, 2021, total of 2,574 reports in all ages/age groups

• Myopericarditis: 1,903 reports

• Pericarditis alone: 671 reports

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Preliminary myopericarditis reports to VAERS following COVID-19 

vaccination by dose number (data thru Aug 18, 2021)

Manufacturer

Reports after

dose 1 

Reports after 

dose 2

Reports after

unknown dose

Pfizer-BioNTech (n=1,282) 169 922 191

Moderna (n=557) 133 339 85

Janssen (n=49) 33 1 15

Not reported (n=15) 2 9 4

Total (N=1,903) 337 1,271 295

 Includes total preliminary reports identified through VAERS database searches for reports with myopericarditis MedDRA* codes and 

pre-screened VAERS reports with signs and symptoms consistent with myopericarditis; excludes reports of solely pericarditis

• Follow-up, medical record review, application of CDC working case definition, and adjudication is ongoing or pending

* Medical Dictionary for Regulatory Activities https://www.meddra.org/ 5
Characteristics of preliminary* myopericarditis reports to VAERS 

following known mRNA COVID-19 vaccination† (data thru Aug 18, 2021)

Characteristics Dose 1 (mRNA only) 

(n=302)†

Dose 2 

(n=1,261)†

Median age, years (range) 26 (12–94) 20 (11–87)

Median time to symptom onset, days (range) 3 (0–71)‡ 2 (0–98)‡

Sex (%)

Male 218 (72%) 1,034 (82%)

Female 78 (26%) 220 (17%)

Not reported/not available 6 (2%) 7 (1%)

* Includes reports identified through VAERS database searches for reports with myopericarditis MedDRA codes, with signs and symptoms consistent with 

myopericarditis, and with dose number documented; and pre-process VAERS reports with follow-up, medical record review, and application of CDC case definition 

for myopericarditis

† Excludes 33 reports after Janssen, and 2 reports that did not specify manufacturer after Dose 1; excludes 1 report after Janssen and 9 reports that did not specify 

manufacturer after Dose 2

‡ Four reports after Dose 1 had onset >71 days; five reports after Dose 2 had onset >98 days 6
Expected vs. Observed reports after mRNA vaccination dose 2, 7-day risk period (N=765)*

Age group, 

years

Females Males

Cases of 

myopericarditis, 

expected

Cases of 

myopericarditis, 

observed

Cases of 

myopericarditis, 

expected

Cases of 

myopericarditis, 

observed

12–15* 0–3 12 1–5 117

16–17* 0–2 15 0–3 121

18–24* 1–8 24 1–11 213

25–29* 1–6 16 1–9 56

30–39 2–21 10 2–19 72

40–49 2–22 22 2–19 45

50–64 4–40 15 4–35 13

65+ 4–44 6 4–36 8

* As of Aug 18, 2021; assumes a 7-day observation window, with 765 of 897 reports after mRNA vaccines occurring during Days 0–6 after vaccination; counts among 12–29 years 

from reports meeting case definition for myopericarditis; expected estimates for females 12–29 years adjusted to reflect reduced incidence in this age group 7
Expected vs. Observed reports after Pfizer-BioNTech dose 2, 7-day risk period (N=549)*

Age group, 

years

Females Males

Cases of 

myopericarditis, 

expected

Cases of 

myopericarditis, 

observed

Cases of 

myopericarditis, 

expected

Cases of 

myopericarditis, 

observed

12–15* 0–3 12 1–5 116

16–17* 0–2 15 0–3 120

18–24* 0–5 11 1–7 134

25–29* 0–4 4 1–5 30

30–39 1–13 7 1–11 40

40–49 1–13 12 1–11 26

50–64 2–22 9 2–19 5

65+ 2–22 4 2–18 4

* As of Aug 18, 2021; assumes a 7-day observation window, with 549 of 765 reports after mRNA vaccines occurring during Days 0–6 after vaccination; counts among 12–29 years 

from reports meeting case definition for myopericarditis; expected estimates for females 12–29 years adjusted to reflect reduced incidence in this age group 8
Expected vs. Observed reports after Moderna dose 2, 7-day risk period (N=216)*

Age group, 

years

Females Males

Cases of 

myopericarditis, 

expected

Cases of 

myopericarditis, 

observed

Cases of 

myopericarditis, 

expected

Cases of 

myopericarditis, 

observed

12–15* 0 0 0 1

16–17* 0 0 0 1

18–24* 0–3 13 0–4 79

25–29* 0–2 12 0–3 26

30–39 1–8 3 1–8 32

40–49 1–9 10 1–8 19

50–64 2–18 6 2–16 8

65+ 2–22 2 2–19 4

Moderna

vaccine not 

authorized 

in 12-17 y/o

* As of Aug 18, 2021; assumes a 7-day observation window, with 216 of 765 reports after mRNA vaccines occurring during Days 0–6 after vaccination; counts among 12–29 

years from reports meeting case definition for myopericarditis; expected estimates for females 12–29 years adjusted to reflect reduced incidence in this age group 

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Care and outcomes

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Care and outcomes of preliminary myopericarditis cases reported to 

VAERS after COVID-19 vaccination in persons <29 years old (N=1,339) 

(data thru Aug 18, 2021)

1,339 total preliminary reports

 742 met CDC case definition* 

of myocarditis or 

myopericarditis

 494 under review

Of 742 meeting case definition:

 701 were hospitalized 

• 667 discharged

‒ 515 (77%) known to have 

recovered from symptoms 

at time of report

• 18 still hospitalized (5 in ICU)

• 16 with unknown disposition

 27 were not hospitalized (seen in 

emergency dept., urgent care, 

outpatient clinic, not specified)

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* Included in: Gargano et al. Use of mRNA COVID-19 Vaccine After 

Reports of Myocarditis Among Vaccine Recipients: Update from the 

Advisory Committee on Immunization Practices — United States, June 

2021. MMWR Morb Mortal Wkly Rep 2021;70:977–982.

https://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7027e2-H.pdf
Reporting rates

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Reporting rates of myopericarditis (per million doses administered), by 

manufacturer, sex, and dose number, 7-day risk period* (as of Aug 18, 2021) 

Pfizer Moderna Janssen Pfizer Moderna Janssen Pfizer Moderna Janssen

(All) (All) (All) (Males) (Males) (Males) (Females) (Females) (Females)

Ages† (yrs) Dose 1 Dose 2 Dose 1 Dose 2 Dose 1 Dose 1 Dose 2 Dose 1 Dose 2 Dose 1 Dose 1 Dose 2 Dose 1 Dose 2 Dose 1

12–15 2.6 20.9 0.0

not 

calc. 0.0 4.8 42.6 0.0

not 

calc. 0.0 0.5 4.3 0.0 0.0 0.0

16–17 2.5 34.0 0.0 14.6 0.0 5.2 71.5 0.0 31.2 0.0 0.0 8.1 0.0 0.0 0.0

18–24 1.1 18.5 2.7 20.2 2.7 2.4 37.1 5.1 37.7 3.0 0.0 2.6 0.7 5.3 1.6

25–29 1.0 7.2 1.7 10.3 1.9 1.8 11.1 3.2 14.9 2.0 0.3 1.3 0.4 6.3 0.0

30–39 0.8 3.4 1.0 4.2 0.4 1.1 6.8 1.6 8.0 0.0 0.6 1.0 0.4 0.7 1.0

40–49 0.4 2.8 0.5 3.2 1.2 0.7 4.4 0.6 4.6 2.2 0.1 1.8 0.4 2.1 0.0

50–64 0.2 0.5 0.6 0.8 0.2 0.2 0.5 0.4 1.0 0.0 0.3 0.8 0.8 0.7 0.5

65+ 0.2 0.3 0.2 0.3 1.0 0.2 0.4 0.4 0.4 1.0 0.2 0.4 0.1 0.2 0.9

* Reports with time to symptom onset within 7 days of vaccination

† Reports among persons 12–29 years of age were verified by provider interview of medical record review 13
Investigating myocarditis health effects 

after COVID-19 vaccination

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Enhanced surveillance for myocarditis outcomes after 

mRNA COVID-19 vaccination in VAERS case reports* 

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 Assess long-term functional status and clinical outcomes among 

individuals reported to have developed myocarditis after mRNA 

COVID-19 vaccination (among reports that met CDC case definition)

 A two-component survey intended to assess outcomes at least 90 

days after onset of myocarditis symptoms

• Patient survey: Ascertains functional status, clinical symptoms, quality of 

life, and need for medication or other medical treatment 

• Healthcare provider (e.g., cardiologist): Gather data on cardiac health 

and functional status

 Timeline: data collection ~ August 2021-November 2021

* https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myo-outcomes.html
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Enhanced surveillance for myocarditis outcomes after 

mRNA COVID-19 vaccination in VAERS case reports* (cont.) 

 Preliminary implementation data

• As of August 18, 2021, VAERS has received 742 reports of 

myocarditis or myopericarditis after COVID-19 vaccination that 

met case definition

‒ Of these, 253 patients are at least 90 days post-myocarditis 

diagnosis

• Data collection is currently underway

* https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myo-outcomes.html
Summary

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Summary

 2,574 reports of myopericarditis or pericarditis to VAERS (as of August 18, 2021)

• 1,903 myopericarditis, 671 pericarditis 

 Epidemiology of myopericarditis following COVID-19 vaccination similar to 

previously reported updates

• Primarily in younger males, after dose 2 mRNA vaccination, symptom onset clustering 

within several days of vaccination,

 Limited follow-up information in VAERS case reports suggests most patients 

(77%) recovered from symptoms at time of report or follow-up

 Observed vs. Expected analysis with VAERS reports

• Males: Observed > Expected in age groups through 49 years

• Females: Observed > Expected in age groups through 29 years

 Enhanced surveillance for myocarditis outcomes after mRNA COVID-19 

vaccination in VAERS case reports is ongoing

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Acknowledgments

 VAERS Team

• VAERS TTS abstraction team

• VAERS Myopericarditis abstraction team

• VAERS Data team

 Clinical Immunization Safety Assessment Project

 COVID-19 Vaccine Task Force Data Monitoring and Reporting Group

 FDA/Center for Biologics Evaluation and Research

Thanks to the many people who made analysis of these data possible:

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The findings and conclusions in this report are those of the authors and do not necessarily represent the 

official position of the Centers for Disease Control and Prevention.

Thank you!

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